Carburetor for obtaining gaseous mixtures for internal combustion engines



June 29, 1943 w. H. G. wUNscl-lv ETAL. 2,322,991 CARBURETOR FOR OBTAINING A GASEOUS MIXTURE l -FOR INTERNAL COMBUSTION ENGINES Filed Sept 28, 1957 4 Sheets-Sheet 2 Hem/Rn H June 29, 1943. w. H. G. wuNscH ETAL 2,322,991

CARBURETOR FOR OBTAINING A G'SEOUS MIXTURE FOR INTERNAL COMBUSTION ENGINES Filed Sept. 28, 193'? 4 Sheets-Sheet 4 .Ffgw 5 Patented June 29, 1943 GARBURETOR FOR OBTAINING G'ASEOUS IVIIXTURES FOR INTERNAL COMBUSTIONl ENGINES Wilhelm 1 Heinrich Gerard Wunsch and: Robert Jean Achille- Rolland, Brussels, Belgium; vested in the Alien-Property Custodian- ApplicationSeptember 28, 193'7, Serial No'. 166,034 InlBelgium September 29, 1'936 Claims.-

The present inventionv relates to carburetors used for producing gaseous-mixtures for internal combustion engines.

It is well known that the gaseous mixtures inten'dedf tof be introduced into internal combustion engines have been obtained hitherto by atomizing the liquidf' fuel in al stream of air drawnin by the engine. As a consequence the fuel is only partially vapourized; and still remains in a vesicular form, or in tiny droplets. The` presence in the mixture of these tiny droplets of liquid` causes various inconveniences. For example when these droplets are in the cylinders offthey engine they burn incompletely and give lrise to harmfulcarbon depositsV on the internal` surfaces of` the cylinders, and also on the ignition devices. This not only causes fouling of the cylinders but also increases theconsumption of petrol.

Furthermore` the gaseous mixtures hitherto have been produced; generallyy speaking, by`

means of delicateI devices-such for example` as spraying nozzles which have apertures of such small section that they become blocked` up, relatively `frequently by dirt and other impurities even of small dimensions.

One off the objectsl of the invention is to remedyy these drawbacks and to avoid totally the stopsnowadaysstill quite frequent as a resultofthe sprayingnozzles being plugged up or obstructed by impurities sometimes of very small volume.

Another'object of theinventionl is to do away' almost completely withthe'fouling of theengine parts coming; into contact withthe explosive mixture, byfthesuppression of the incomplete conribusticn of the fuel droplets.

A further object is the obtainment of a perfeet mixture made to suit accurately the different speeds of the engine and to attain thus a substantial' saving. of fuel. i

Stillanother object is to ensure the possibility of a. perfect control withsimple means.

With these objects in View; our invention essentially consists-inthe special arrangement andA combination-of parts hereinafter fully described. and. pointed-outin the appended'claims.

On: the annexed drawings:

Figure l isaverticalsectional view of a car'- buretor according:` to the1 invention, with a vaporizingch'amb'erpartlylled'with fuel to be vaporized;

Figure 2"issa `vertical section 1 taken` on aplane` perpendicular to thesectional plane of -11 and` passing through the axis of ther air inlet conduit to the engine.

Figure 3 is` al` section similar to that' of Fig. 1 showing a second form of construction of the carburetor with alvaporizing chamber containing noliquid fuel.

Figurel 4 shows a section, similar to that of Fig. 2, of the carburetor according to Fig. 3.

Figure 5 is a vertical section of`a third form of carburetor having a preliminary vaporization chamber providedwithv an automatic air valve regulated'bythe vacuum existing in the Vaporizing chamber.

Figures 6 and'lV represent respectively a projection on ahorizontal plane of the upper and lower faces of the carburetor shown in Fig. 5.

Figure 8 is a verticaldsection, passing through the axis of the air supply pipe to the engine, of a fourth lf'orm of" construction oi" carburetor according to the invention, having a preliminary vaporizationA chamber with obturators or flap valves that are not automatic, but operate mechanically.-

Figure 9 is a projection on a horizontal plane of thecarburetor'shown inFig. 8;

In Figs. 1l and'2, Iindicates an'liermetically closed vaporization chamber which contains a certain quantity of liquid fuel 2', kept ata constant" level by means of a' float 3"which controls the closure of`a needle valve d'through the'intermediaryof a lever 5` pivoting about an axis 6.

This needle valve closes or opens a pipe l A perforated side a tubular conduit 8`through which the air supply is drawn by the engine in the direction indicated', by the arrow. A regulating buttery`valve=9,` fixedto a spindle l0, is capable of pivoting through a quarter of arevolution so as to closeorv open the section of the conduit 8 to avertv or permitthe passage of air to the engine.

A pipe or ,channel IlY bent into the direction of the engine opens into the conduit 8.' The mouth I2l ofthe pipe il', directed towards the engine, opensin-the axis of adiffuser I3 fixed in the interior of the conduit 8. The pipe Il provides communication between the vaporizing chamber Iv andthe conduit 8.

ported in a bearing I4 so constructed as not to allow any infiltration of air from the exterior into the interior of the vaporizing chamber I. This spindle II) carries a sleeve I5 to which is attached a resilient metallic part acting as the obturator I6, this metallic part being. of such form, for example in the form of a sector, as progressively to uncover with its external edge the hole I1 formed by the end of the pipe II. The oscillatory movement of the obturator I6 corresponds to that of the butterfly Valve 9.

The conduit 8 terminates at the end nearest the engine in a flat part or base I8 which enables the carburetor to be fixed to the inlet manifold of the engine.

Finally the spindle I0, Whose end remote from the chamber I also passes through the wall of the conduit 8, has xed to it a lever arm I9'terminating in a swivel joint 20 to which the engine speed control member is adapted to be applied.

The carburetor described above operates in the following manner:

When the engine is started up, either by the self -starter or by hand, it creates a vacuum in the air admission conduit 8, so that the outside air drawn into this conduit flows towards the engine in an endeavour to fill up this vacuum, The

vacuum is Aalso transmitted by way of the tube t I I to the chamber I, so that a certain vacuum is also set up therein. The fuelin the chamber I immediately starts to b-oil and the fuel vaporiZeS, (thereby filling the free part of the chamber I with gasoline vapour. This boiling ,continues until complete saturation of the space-above the surface level of the fuel is attained. The engine, continuingrto run, maintains the vacuum in the conduit 8, and the fuel vapour naturally ows through the part I1 and the channel II into the conduit 8, where it becomes intermingled with the air passing towards the engine. This ex- -plosive mixture enters the cylinders of the en-` gine, and the latter then continues to operate automatically, maintaining a vacuum in the conduit 8.

As the fuel vaporizes in the chamber I the surface level of the liquid drops, thus lowering the float 3,`which operates the lever 5, causing the latter tofpivot about its axis 6 and to liberate the needle valve 4 so as to permit the entry of more fuel byr way of the pipe 1 to restore the fuel surface level Vto its original and normal point. The fuel vaporized is thus replaced progressively and its surface level kept constant in the vaporizing chamber I. Y y

Furthermore, as the valve 9 is rigidly and positively associated with the obturator I6 through the intermediary of the shaft I0, the result is that when the accelerator opens the valve 9 by means of members 20 and I9 to increase the feed to the engine, the obturator progressively uncovers the port `I1 simultaneously, thus permitting the passage of a quantity of fuel vapour proportional to the air sucked in by the engine. This proportion can be predetermined by the external contour of the obturator I6. Thus it is possible, with a suitable obturator and a port I1 of appropriate size, to obtain that mixture of fuel and air which -is most perfect andrnost favourable at all speeds of the engine.

Figs.'3 and 4 show another form of carburetor in which the vaporizing chamber does not contain any fuel. In these figures, the vaporizing chamber I is likewise arranged alongside a conduit Bconveying air to the engine. As in the examplefaccording to Figs. 1 and 2, this conduit aeaam contains a butterfly valve 9 mounted on a shaft I0 operated by a lever I9 and a ball and socket joint 2i). Beneath the valve 9 there is again a diffuser I3 in the axis of which is located the mouth I2 of a pipe II directed towards the engine and communicating by way of a port I1 with the vaporizing chamber I. The shaft Ill also passes through this chamber, but does not y carry a device for closing the port I1, which thus remains continuously open. The shaft It) has fixed to it a resilient piece of metal or obturator 2| of such form as to permit the port 22 by which the fuel supply pipe enters the chamber I to be uncovered. In this case therefore it is not the quantity ofthe fuel vapour emerging from the vaporizing chamber I which is regulated, but

the quantity .of fuel which is allowed to issue between the pipe 1 and the port I1 of the pipe II.

With this construction, the fuelis introduced into the chamber I progressively and proportionally to the amount of explosive mixture serving to feed the engine. As-.the metallic part 2l is shifted simultaneously with the butterfly valve 9 it is possible, by giving this member 2 I an appropriate external contour, to regulate the quantity of fuel to be vaporized in accordance with the amount of` air sucked in by the-engine. In order to prevent waste of fuel Vapor sucked by the engine when the valve 9 is closed suddenly, a second obturator may be provided in the chamber I over the port I1 through which this vapor emerges. Such obturator would also be controlle by the operationof-the valve9.

In a third embodiment of the invention shown in Fig. 5 to '1, the apparatus comprises a cylinder 3| (rotating in a box) articulated on a shaft 32 and having a window or slot 33 formed therein.

This aperture 33 is variable in depth and width, increasing from the very lowest depth and width up to its maximum.

l Against the cylinder SI there is applied a fibrous part 31 (or this part may be made of 33 flows into the vaporizing chamber 40 by way i f of the channel 65. The movement of the cylinder 3l is synchronized with that of the throttle valve 54 of the carburetor by means of levers 38, 38 and 38 or by any other suitable means.

The vaporizing chamber indicated at 40 is surrounded by a water chamber lil. The warm water coming from the cylinder head by way of the pille` i2 is evacuated by way of the port 4 3. A tubular grid 44 of variable delivery, through whichvpass the hot exhaust gasesof the engine, completes the 'heating arrangement.

A channel i6 coming from the vaporizing chamber iii opens into the tubular passagel 51 by way of which the air flows towards the engine in the direction of the arrow. This channel 46 could beso arranged as to be capable of being advanced or retracted, either mechanically or automatically, Vin such a way that its Vouter extremity where it opens into the air passage 51 is always at the place Where the best vacuum exists.

, A device ,for regulating the vacuum in the vaporizing chamber and for regulating the amount of air for supplying thefengine is also provided, and is constructed inthe following manner:

An obturator 41 composed of two or more lamellae Y(or in any other appropriate manner, such forexample as twohollow concentric cylinders provided with windowsand sliding one upon the other) works either like an ordinary diaphragm such as those used in photographic cameras, or else, vand as is preferred, in the manner shown in Fig. 6. It is made up of two superimposed plates 41' and 41" articulated upon an axis 58. These plates are pierced with apertures 59 and 60 of appropriate and determined form, in such a. manner that in shifting one over the other they-constitute a variable aperture 36 having as its centre the place where the extremity of the gasied fuel supply channel 46 opens. These two plates move in opposite directions and are-controlled by levers 6I and 62 pivoting in a connecting rod 48 attached at its other end to a piston 49 moving in a cylinder 59 closedat its opposite end. The piston is urged towards the right by the spring l, whose pressure is adjustable by means of the screw-threaded plug 52. This cylinder 50 is in communication with the vaporizing chamber 40 by wayof the channel 53. A butterfly valve 54 adapted to close the air supply conduit 51 is articulated on the shaft 55, which is controlled by the lever 56 `connected with the engine accelerator.

The carburetor `just described operates in the following Way:

When the engine is stopped, the obturator 41 is quite closed owing to the pressure of the spring 5|. rThe throttle 54 occupies a position that permits the quantity of fuel gas to pass, that is necessary for slow ruiming of the engine.

As soon as the-engine isstarted it sucks the air located behind the throttle 54, the obturator 41 and the air combined in the .vaporizing chamber 40, The vacuum created yin the latter communicates itself by way of the channel 53 to the cylinder Sil. The piston 49 is -then drawn towards the left, thus causing the obturator 41 to open. The air entering by way ofthe channel 51 endeavours to llup the vacuum existing'behind the obturator 41.

From this moment the air drawn in from the exterior by the passage v51 in the direction of the arrow, by its rapid passage past the aperture 36 of the obturator 41, maintains the vacuum existing in the vaporizing chamber 40, in correlation with the` suction of the engine.

As the throttle 54 is opened, so does the airdraft of the engine increase, and the vacuum existing at the place where the channel 46 terminates at the aperture 36 of the obturator 41 becomes greater and greater. This vacuum is transmitted to the vaporizing chamber40, and thence the channel 53 to the cylinder 50. The piston 41 is thus shifted towards the left, and by means ofthe connecting rods 48 it widens the aperture 36 of the obturator 411 until equilibrium with the pressure of the spring 5I is reached. The vacuum existing in the chamber 4U and cylinder 5.5) thus increases with the speed cf the engine and widens the aperture 36 of the obturator 41' proportionally.

It will be seen that at the same time as the throttle valve.` is openedthe-cylinder 3! is pivoted aboutits axis through the intermediary of levers 38, 38 and 38, thus shifting the'window 33 over the port 34 and, according to its position, liberating the amount .of fuel necessary at the existing speed ofthe engine. This fuel, entering the vaporizing chamber 40 by way of the channel v45, is gasied owing to the vacuum that exists in said-chamber, this vaporization being enhanced bythe heating `grid `44. The calories absorbed by the vaporization of the fuel are then restoredby the heating system 44 and the water chamber 4I. Y

The fuel thus vaporized is` sucked through the channel 46 from whichit issues at the aperture 36 of the obturator 41 rin the passage 51, where it mixes with theair from the exterior, the vexplosive mixture-thus formed being sucked in by the engine.

In addition to the advantages inherent to the preliminary vaporization of the fuel, this construction permitsa better charging of the engine cylinders, owing to the fact that it is possible to eliminate the heating Iof the gaseous fuel and thus-give the `engine a less expanded gas. The volumetric output l of vthe engine'will thus be substantially improved.

The obturator 41 could obviously be operated mechanically and independently of the vaporizing chamber by connecting it in appropriate manner to the movement .of the throttle 54. The cylinder 55 and its accessories would be suppressed in-this case.

Figs. 8k andi) show yet another form of carburetor in which the throttle valve and the obturator forma Single mechanically operated unit.

The carburetor is here composed of a cylinder 63 pierced by a channel 64 pivoting with slight friction in a box 65 about its axis 32 operated by the lever Y38. This -box 55 is-provided with two Windows or apertures cri-operating with two chan.. nels constituting the air passage 51. The Vaporizing chamber is .here represented by the hollow cylinder 3! fixed .to the cy1inder63 by a nut 55 which .permits it to lbe adjusted. Gn the exterior of the cylinder 3! there is formed a slot 33 which communicates with the interior by way of the passage 61. From the interior of the vaporizing `chamber runs a channel 46'opening into the channel 64. The hot water chamber 4I for restoring the calories .absorbed by the vaporization of the fuel, is here arranged in the form of a cover aroundthe cylinder 3| forming the vaporizing chamber. The fuel arrives by Way of the channel 35 from which it emerges at the aperture 34 in front of the slot 33.

The carburetor just described operates in the following manner:

By pivoting the cylinder 63 about its axis, the apertures of the air passage 51 are opened proportionally and at the same time the slot is shifted relatively tothe aperture 34, thus increasing the delivery of fuel proportionately. The air sucked in from youtside in the direction of the arrow creates a vacuum in the channel 46 by its rapid passage in the channel 64. This vacuum is transmitted to the vaporizing chamber 40,*thus sucking the fuel liberated by the slot and aperture system. The vaporized fuel escapes at the end of the channel 64 where it becomes mixed with the air entering from outside, thus forming the explosive mixture for feeding the engine.

It is easy to see vthe great advantages of this methodrof obtaining a gaseous mixture 'by prelimina-ry vaporization of the fuel before it is mixed with the air. The-explosive mixture no longer contains liquid fuel in the form of tiny droplets, a phenomena which could not be completely eliminated in the previously existing apparatus. The

explosive mixture formed by preliminary vaporization is perfect and can be adapted exactly to the different speeds of the engine, it being of course well-known that the mixture should not be the same for all speeds. There is consequently a substantial economy of fuel with an equivalent performance of the engine, in as much as the apparatus prevents incomplete combustion of droplets of fuel which were present in all the gaseous mixtures produced heretofore.

The apparatus devised for carrying out the process according to the invention is of great simplicity and of cheap construction. It permits perfect regulation .by suitably shaping the exterior edge of the obturator controlling either the delivery of fuel vapour or the arrival of liquid fuel.

The employment of a carburetor of the kind described permits the complete avoidance of those stoppages that are so frequent an occurrence at present, and which are due to the nozzles of the carburetor becoming blocked up with particles of dirt, which are sometimes very small in size.

Finally, owing to the elimination of incomplete combustion of droplets of fuel, there is practically no fouling of the parts of the engine in contact with the explosive mixture. It is evident that a carburetor of the kind described could, if desired, be finished off with certain accessory devices, such for example as the devices, for heating the liqui-d fuel so as to restore the calories absorbed by the vaporization and to maintain the vaporizing chamber at a temperature permitting more rapid Vaporization of the fuel, Finally, owing to its simple and rational manner of operation, a carburetor of the kind described can be used for all kinds of liquid fuels, (petrol, benzole, etc.) without necessitating any modification of the apparatus other than the installation of the obturator which is most appropriate to the fuel employed.

What we claim is:

1. A charge forming device, comprising a vaporizing chamber provided with an inlet port for liquid volatile hydrocarbon, the cross-section of said chamber considerably exceeding that of said port, a conduit adjacent said chamber, the opposite ends of which respectively are adapted to be placed in communicati-on with a suction creating device and with atmosphere, means creating a sub-atmospheric pressure within said chamber and withdrawing volatilized hydrocarbon therefrom, said means comprising a pipe, one end of which communicates with said chamber and the other end of which is positioned within said conduit with the open end thereof directed toward the means for connecting said conduit with the suction creating device, an adjustable obturator in said conduit rearwardly of the open endy of said pipe to vary the air flow cross-section of said conduit and means for delivering a supply of liquid volatile hydrocarbon to said vaporizing chamber at such a rate that no substantial liquid level is maintained in the vaporizing chamber.

2. A charge forming device, comprising a vaporizing chamber provided with an inlet port for liquid volatile hydrocarbon, the cross-section of said chambei1 considerably exceeding that of said port, a conduit adjacent said chamber, the opposite ends of which respectively are adapted to be placed in communication with a suction creating device and with atmosphere, means creating a sub-atmospheric pressure within said chamber and withdrawing volatilized hydrocarbon therefrom, said means comprising a pipe, one end of which communicates with said chamber and the other end of which is positioned within said conduit with the open end thereof directed toward the means for connecting said conduit with the suction creating device, an adjustable obturator in said conduit rearwardly of the open end of said pipe to vary the air flow cross-section of said conduit, a throttle valve in said conduit forwardly of the open end of said pipe, means for delivering a variablesupply of liquid volatile hydrocarbon to said vaporizing chamber, and a linkage connecting said throttle with said regulating means to increase the amount of liquid volatile hydrocarbon supplied to said vaporizing chamber, as the throttle is opened, at such a rate that no substantial liquid level is maintained in said vaporizing member.

3. A charge forming device, comprising a vaporizing chamber provided with an inlet port for liquid volatile hydrocarbon, the cross-section of said chamber considerably exceeding that of said port, a conduit adjacent said chamber, the opposite ends of which respectively are adapted to be placed in communication with a suction creating device and with atmosphere, means creating a subatmospheric pressure within said chamber and withdrawing volatilized hydrocarbon therefrom, said means comprising a pipe, one end of which communicates with said chamber and the other end of which is positioned within said conduit with the open end thereof directed toward the means for connecting said conduit with the suction creating device, a throttle valve in said conduit, a throttle valve operating lever, a cylindrical casing provided in its cylinder wall with an inlet and an outlet passage for liquid volatile hydrocarbon, said outlet passage being connected with the inlet port of said chamber, a solid cylinder fitted rotatably in said casing and being provided with a peripheral groove connecting said inlet and outlet passages, said groove having a peripheral length exceeding the peripheral distances between said two passages and a cross-section increasing from one end to the other of said groove, a lever to adjust said cylinder for admission of a greater or smaller quantity of liquid volatile hydrocarbon into said groove, and a link connecting said throttle valve operating lever with said cylinder adjusting lever to increase the amount of liquid volatile hydrocarbon supplied to said chamber, as the throttle is opened, at such a rate that no substantial liquid level is maintained in said vaporizing chamber.

4. A charge forming device, as claimed in claim l/VILHELM HEINRICH GERARD WUNSCH. ROBERT JEAN ACHILLE ROLLAND. 

